''' aliens.py: 遍历aliens的列表 '''
alien_0 = {'color':'green','points':5}
alien_1 = {'color':'yellow','points':10}
alien_2 = {'color':'red','points':15}

aliens = [ alien_0, alien_1, alien_2 ]
for alien in aliens:
    print(alien)

aliens = []
for alien_number in range(30):
    new_alien = {'color':'green', 'points':5, 'speed':'slow' }
    aliens.append(new_alien)

for alien in aliens[:5]:
    print(alien)
print("...")
print("Total number of aliens: " + str(len(aliens)))

aliens = []
for alien_number in range(0,30):
    new_alien = {'color':'green', 'points':5, 'speed':'slow' }
    aliens.append(new_alien)

for alien in aliens[0:3]:
    if alien['color'] == 'green':
        alien['color'] = 'yellow'
        alien['speed'] = 'medium'
        alien['points'] = 20
    elif alien['color'] == 'yellow':
        alien['color'] = 'red'
        alien['speed'] = 'fast'
        alien['points'] = 15

for alien in aliens[:5]:
    print(alien)
print("...")


